<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>相对定位</title>
    <style>
        div{
          width: 100px;
          height: 100px;
          border: 1px solid red;
        }
        div:hover{
          /*相对定位：元素不脱离文档流*/
            position: relative;
          /*通过left/right/top/bottom相对于元素初始位置偏移*/
            top: 20px;
            left: 20px;
        }
    </style>
</head>
<body>
<div>div1</div>
<div>div2</div>
<div>div3</div>
</body>
</html>